Method and apparatus for generating heating medium



Dec. 28, 1937. c. A. DUNHAM ET A1.

METHOD AND APPARATUS F OR GENERATING HEATING MEDIUM Filed Dec. 3l, 1954 5 Sheets-Sheet l /Lll 11111111lllllnllllll/III/L Izzi/111111111111111. r

lll/11111111111vll/111111111111 Ill/111111111, /lll//lIlI/llllll[lill/III 111111111111 'll/1 Il Dec. 28, 1937. c. A. DUNHAM Er An.

Filed Dec. 31, 1934 METHOD AND APPARATUS FOR GENERATING HEATING MEDIUM Dec. 28, 1937. c. A. DUNHAM Er A1.

METHOD AND APPARATUS FOR GENERATING HEATING MEDIUM Filed Dec. 3l, 1934 Patented 28,1931 'A y 2.10am

vPATENT OFFICE muon aan Arrm'rus ron Gassner- ING HEATING MEDIUM Clayton@ Dnnhamand Anbra R. Dunham, Glenooe. lll.. assignors to yExperimental laboratories Incorpora ytinmoflllinois Chicago. Ill., a corpora- Anuman December 31,1934, serial No. 'Isaacs In Canada June 4, 1930 s claim.. (ci. zar-*1i This invention relates to a new and improved process and apparatus for generating a heating medium consisting of mixed steam and products of combustion for use in a heating system.

In the type of heating system to which this invention relates. fuel is burned in proximity to an enclosed body of water and the products of combustion are passed ln intimate contact 'with thewater so as to form steam, and the heating l, medium consisting of the mixed steam and products .of ycombustior'l is delivered into4 radiators wherein the steam is condensed and also a large portion of the heat from the products of combustion is utilized f or heating purposes. The

l5 cooled non-condensable gases are withdrawn fromthe radiators, thus causing the continuous circulation of the heating medium, andthe con'- densate from the steam is returned to the gen- :i of generating apparatus shown in Figs. 5 and 6 was first disclosed in our application Serial No. 376,537. 'Ihe apparatus shown in Figs. 3 and 4 was first disclosed in our application Serial No. 558,293. A form of generator utilizing most of 35 the features shown in Figs. 3 and 4 was first disclosed in applicationserial No. 466,002.

Briey described, this generating apparatus comprises a closed housing in which is confined a combustion chamber wherein the fuel is 40 burned. The housing encloses a combustion space and mixing chamber which is substantially surrounded by a body of water. and another body or bodies of water are supported within the space in the path of the combustion gases so as to be sitioned atthe'greatest elevation is replenished by condensate returned from the heating system so that the process is continuous.

The principal object of this invention is to provide an improved process and apparatus for generating mixed iluid heating medium, such as briey described hereinabove and disclosed more in detail in the specifications which follow. s.

Other objects and advantages of this invention will be more 'apparent from the following detail 10 description of certain approved forms of apparatus constructed and operating according to the principles of this invention. 1

In the accompanying drawings:

Fig. l is an elevation showing the principal l5 elements offa heating system in which a generator of this-type is used.

Fig. 2 is an-felevation, partially in section, of one of the radiator inlet valves.

Fig. 3 isI a vertical central section through a 20 preferred typeof generator.

' Fig. 4 is a horizontal section taken substantially on the line 4 4 of Fig. 3.

Fig. 5 is a vertical section throughV another form of generator.

Fig. 6 is a vertical section through the automatic fuel-control valve shown in Fig. 5.

Referring first to the general heating system as indicated in Figs. 1 and 2, the improved generator A discharges heating medium through the main supply pipe I and through the branch pipes 2 connected through^inlet valveslB with the several radiators C. Each of-these -inlet valves B includes a cut-oi! valve of usual type operated by the hand-wheel 3 and includes an oriilce plate 35 4 through which the heating medium y,is admitted 'to the'radiator. The oriilces l may @be made of different sizes, in accordance with the/capacity of the individual radiator and its position in the heating system, so that the heating medium will 40 be properly distributed amongst the several radiators. Branch return pipes 5 lead from the several radiators into the main return pipe 6. The exhauster l operated by motor 8 is connected through branch pipe 9 with the lower portion l0 45 of return main 6, this exhauster withdrawing cooled non-condensable gases from the radiators and discharging these gases into the iiue i I. The withdrawal of these gases, together with the condensation of steam in the several radiators, causes a partial vacuum extending back tothe generator A so as to withdraw the heating medigravltythroughtheretiunpipesl, l and Il,and thence through pipe I! back` into the generator A. Additional water can be supplied whenever necessary, as when starting the system. through pipe I8 provided with valve I4. A scale-collectingpochetanddrainconnection Ilmaybeprovided at the lower end of return pipe il. Heating systems of this and automatic controls for the burners 4and the exhausting mechanism. not here shown, are' disclosedmoreindetailandclaimedinourthree oo-pending applications hereinabove referred to.

The form of generating apparatus shown in Figs. 3 and4 will nowbe described.L An essential characteristic of this generator is that it is entirely closed except for the inlets for water, fuel and combustion air, and the outlets for the heating medium and excess water. None of these, except the inlet for combustion air, has any direct connection with the atmosphere within the building so that a reduced pressure may be' maintained within the generator and the escape of fluid therefrom is prevented. The generator may lbe made of metal or suitable refractory materials, or both, preferably comprising an outer metallic shell covered with suitable insulating material (not here shown) in order to minimise heat losses. A lower substantially closed metallic housing Il rests upon and is sealed to a concrete supporting base I1 formed with the sump Il from which leads drain pipe Il which may empty into the sewer connection indicated at 2l. A side extension 2| of the lower casing Il houses'the burner assembly 22 which includes the main burner 2l for projecting the combustion materials into the combustion chamber. The burners are controlled by the assembly indicated at 24 which may be ot the type disclosed and claimed in our copending application Serial No. 558,293. Combustion air is admitted to the casing 2| through any suitable opening.

suitably mounted in and supported by the metallic cover plate 2l of lower casing Il is the main lower combustion chamber 2O formed of.

suitable refractory material. The refractory shell 2l may be supported in a metallic casing 21 formed with a lower inwardly extending supporting ilange 28 and supported from cover plate 2! by the angle brackets. The central cylindrical combustion chamber Il is open at its upper end and provided adjacent its lower end with a tangential inlet opening 2| through which the fuel and air from main burner 23, and the combustion air, enter the' combustion chamber It. Due to this tangential opening, the combustion uids andname take a spiral or spinning path through the combustion chamber 30 whereby a very long flame and complete combustion may be attained almost entirely within the relatively small combustion chamber before the hot products of combustion pass upwardly into the mixing chamber 32.

The outer substantially cylindrical metallic shell Il of the steam generator and mixing chamber is supported by the cover plate 2l or forms an upward extension of lower casing I0. The dome or cover I4 on casing ll leads up to a centra] outlet opening 35 which communicates with the release valve casing '3l from the upper portion of which leads the main supply plpe- I through which the heating medium is conducted to the radiating system. The release valve casing II is formed so that water will drip downwardly through opening 3l, and is provided with the flap or closure -3'I hinged to the casing at 3l type. provided with manual' ,iosmo and held by gravity against the inclined seat II. 'lheflapvalvewill alsobeheldtoitsseatbythe outer atmospheric pressure when the system is normally operated under a partial vacuum. Ii'. for any reason, high pressures should be develope'din th'esystenathisiia'p valvewillblowopen andrelievepressure. 'I'hei'iapmayalso beraised at any time for observation purposes. y

The inner metallic, shell 4I is formed at its top with a dome 4I provided with a central opening 42 through the downwardly extending cylindrical overilow flange 4l. This centrall opening 42 is also in vertical alignment with the outlet conduit I and serv as an outlet for the heating medium from the mixing chamber 32. The annular space 44` between inner and outer shells 4l and Il is normally nlled with water up to the level of overflow opening 42, through which excess water hows downwardly into chamber 32. as indicated by the drops 4B. A shallow ilash plate or pan 48 is supported by legs 41 from cover plate 2l, the flash plate 4l being positioned substantially centrally within the mixing chamber 22. A water heating pan or container 4I is supported beneath overow opening 4,2 by the central post 48 extendingupwardly from flash plate 4l. The upwardly extending sidewalls of 4pan 4l are provided near their upper edges with a circumferentially extending series of restricted outlet openings or slots Il. 'Ihe water falling at 4l through outlet opening 42 will accumulate in heating pan 4l up to the level of outlet openings Il through V zich the heated water (that is the water that not already been vaporized) will overilow as indicated at II onto the ilash pan.4. The purpose of the overflow openings lll is to secure a better distribution of the overilow water in case heating. pan 4l is not exactly level.

'I'he water supply pipe I2 (already described) communicates with the annular water space 44 so as to return condensate into this container. 'I'he pet-cocks l2 and BI are provided to check the upper water level, end drain plug I4 is provided so that the container 44 may be drained and flushed out. As additional water slowly accumulates in space 44 due to the return of condensate from the heating system, the water will overilow through opening 42 into heating pan 48 and thence overow again onto flash pan 46 as already described.

In operation, the highly heated products of combustion rising from combustion chamber 30 pass under and around the ilash plate 4l so as to convert all or the greater portion of the iilm of water thereon into steam. The products of combustion also contact with the water falling through or from overow opening 42, as indicated at 45, and from heating pan 48 as indicated at Il, whereby additional steam is generated. The rising products of ycombustion will highly heat the water in pan 48 so that some steam will be generated from this body of water,` and so that the water which drops onto the ilash pan 46 will already be raised to a high temperature. The hot gases rising through mixing chamber 32 will heat the annular body of water in container 44 so that additional steam is generated from this water, all of the mixed gases consisting of steam and products of combustion passing out through the main supply pipe I to the. heating system. It will be noted that the mixing chamber 32 is entirely closed at its lower end except for the inlet opening for the llame and combustion air at 3l through combustion chamber 30. and the only outlet being through the supply main I throughV which the heating medium passes out. The entire generator will preferably be protected by an outer covering of insulating material (not here shown) so that the heat losses will be minimized and practically all of the heat generated is carried out through the radiating system by the heating medium discharged through pipe I.

ySince practically all of the condensate from the radiating system is returned to the generator through pipe I2, and since additional water is always being formed in the combustion process from the hydrogen in the gas and the oxygen in the air, there will ordinarily be a surplus of water supplied to the generator. Any excess of water that is not vaporized on iiash pan 46 will overflow, as indicated at 55, and then drain out through pipe 56 provided at its lower end with water-seal 51, thence iiowing through drain pipe I9 to the sewer connection at 20.

In the modified form of generator shown in Figs. -and 6, the outer casing comprises a bottom wall 56, vertical cylindrical side walls 59 and a dome shaped roof or cover 60 from which leads the supply pipe I for conducting the heating medium. to the radiating system. The main inner container consisting of bottom wall 6I and inner and outer cylindrical walls 62 and 63 forms an annular container or basin for the main body of water indicated at 64. A pan'65 open at its upper side and comprising an upwardly dished bottom wall 66 and downwardly converging side walls 61 is supported on the top of the inner cylindrical wall 62. The pipe I2 for returning condensate and supply water extends inwardly through the outer casing 59 and has a downwardly projecting discharge leg 66 extending beneath the water level in pan 65 so as to form a water seal.

The air inlet tube 69 projects upwardly through the bottom walls 58 and 6I and extends centrally upward within the lower -portion of the inner annular wall 62 so as to form a third water container or reservoir of annular form. The air inlet pipe 1I leads in through one wall 12 of the building from the outer atmosphere and connects through fitting 13 with the lower end of the air inlet tube 69. The supply pipe 14 for gas or other fuel extends inwardly through a closure plug in one end of fitting 13 and terminates in a burner nozzle 16 of suitable form near the upper end of portion of cylinder 62 constitutes a main combustion chamber, the flame being indicated at 16. Any suitable means may be utilized to ignite the fuel. An opening closed by removable plug 19 may be provided in the outer casing 59, vthrough which opening a lighted taper or an electric sparking device can be inserted to initially ignite the gas after which plug 19 is replaced to seal the opening. A plurality of circular series of open ings 66 and 8| are formed in the cylindrical wall 62 to permit the products of combustion to pass from chamber 11 into the main chamber within the outer casing. The llower openings 6I also determine the water level in the outer reservoir 64. A water discharge pipe 64 leads from a tting 65 in the air inlet pipe 1I, pipe 64 being looped upwardly at 66 to provide a water seal against the entrance or escape of gases through this pipe.

,The gas' supply pipev 61 leads from theoutside source of gas supply to the valve chamber 69 of the automatic control valve indicated generally at D, the supply pipe 14 leading from this valve chamber to the burner 16. One suitable. form of control valve is indicated diagrammatically in Fig. 6. A valve plate 69 is adapted to engage with the valve seat 90 to cut on the flow of gas or other fuel through the valve. Valve stem 9I leads up- 92 housed in a diaphragm casing 96. The chamber 94 beneath the diaphragm 92 is open to atmospheric pressure through aperture 95. The chamber 96 above diaphragm 92y is connected through pipe 91 with the interior of generator A', whereby diaphragm chamber 96 will always be under substantially the pressure existing in the generator. A sealing diaphragm 99 ofthe flexible bellows type is connected between the valve casing 99 and the valve plate 69 to prevent the escape of gas around valve stem 9|.

When the chambers 94 and 96 at the two sides of diaphragm 92 are both under atmospheric pressure and diaphragm 92 is in its normal central position, the valve plate 99 will be held against valve seat 99 to close the valve. Ii',de sired an auxiliary spring 99 may be employed for holding the valve against its seat. lWhen the pressure within the generator A is lowered below atmospheric pressure, the pressure in chamber 96 above diaphragm 92 will be correspondingly lowered and the atmospheric pressure within chamber 94 beneath the diaphragm will lift the valve so as to permit gas to ow from pipe 61 to pipe 14 and thence to burner 16. The greater the vacuum within the generator, the lower the pressure above diaphragm 92 and consequently the greater pressure differential will be exerted on this diaphragm to open the valve so that the supply of gas admitted to burner 16 will be increased proportionately as the pressure is lowered within the generator. A very small pipe IM, provided Awith a normally open stop cock IUI, is shunted around valve D to connect gas supply pipe 61 with gas pipe 14 so that a small flow of gas to the burner 16 will always be permitted, whereby a small pilot flame, insufficient for normal heating purposes, is maintained even though valve D is closed.v

In operation, water ilows into the generator A through pipe I2 and is discharged through outlet 69 into the pan 65. When this pan is completely .iilled it overflows in the form of drops falling from the upper edge of the pan into the annular basin or reservoir 64, and in the form of a` thin Iilm owingdown the inclined walls 61 of the pan. Any excess of water in reservoir 64 ows through openings 6I and down the inner surface of inner annular wall 62 into the reservoir 10. Any excess of water in reservoir 19 iiows d own through air tube 69 and out through' pipe 1I and the discharge pipe 64 to the sewer.

Assuming that a partial vacuum exists within the generator, valve D will be opened to admit fuel gas to the burner 16, and air will be drawn in through supply pipe 1I on account of the lower pressure existing within the generator. The gas and combustion air will be ignited within combustion chamber 11' and through the surrounding walls will heat the water in the several reservoirs. As the bodies of Water in receptacles 64 and 65 are` heated, the water will expand thus causing an overflow in contact with the rising products of combustion. These products of combustion pass out through the openings 66 and 9I and contact directly with the exposed surface of the water in the several containers and also with the water dropping from the pan 65 and with the thinillms of water owing down the outer surfaces ofthe containers 65 and 64. The heating medium consisting of the mixed steam and products of. combustion passes out through wardly from valve plate 69 to a exible diaphragm supply pipe I to the radiating system. As the pressure is further lowered within generator A'-, the valve D will be further open'ed to admit a greater quantityof fuel gas and a proportionately greater flow of combustion air will be drawn through pipe 1I into the generator. This provides more rapid combustion and a larger flame 18 and consequently increases the rate of steam generation. When the pressure within generator A' rises to atmospheric, valve D will be closed to cut oil the supply of gas and no more combustion air will be drawn in through inlet pipe 1I.' The generator will therefore practically cease to function, although a small pilot flame will be maintained as hereinabove described. It will -be noted that the pilot llame is substantially surrounded by the bodies of water always present in the generator so that a large portion of the heat from this pilot lflame will be absorbed by the water. This minimizes the heat loss and the pre-heated water in the generator expedites the re-starting of the normal generating process.

It will be noted that in both of the examples herein disclosed the combustion chamber is practically surrounded by bodies of water so that the water will be rapidly heated, and the gases of combustion subsequently passed in intimate contact with the surfaces of these bodies of water and also with water overflowing to the combustion gases so that an adequate volume of steam will be generated and heat losses will be minimized. The condensate from this heating medium is returned to the body of w'ater positioned at the greatest elevation, and since the total water in the system is continually being supplemented by the water formed in the process of combustion, no additional water will ordinarily be required after the generator receptacles are first filled. Only such water as is in excess of the requirements will be drained from the system. In this way the system is always ready to start without the necessity of replenishing the water supply. The generator is completely closed except for the inlets for the several fluids used in the generating process, and since a subatmospheric pressure is normally maintained in the generator, the entrance of these fluids will be facilitated, and the escape of combustion gases from the generator' will be prevented, except through the supply main I.

We claim:

1. The method of supplying a mixed fluid heating medium consisting of products of combustion and steam. consisting in burning fuel within a closed combustion space substantially surrounded by a body of water, the water overnowing within the space in contact with the rising products of combustion, withdrawing the mixed heating medium from the closed space, and returning condensate from the withdrawn heating medium to the body of water.

2. The method of supplying a mixed fluid heating medium consisting of products of combustion and steam, consisting in burning fuel within a closed combustion space substantially surrounded by a body of water, the water overowing within the space through the vproducts of combustion into a second body of water supported in the upper portion of the combustion space, withdrawing the mixed heating, medium from the closed space, and returning condensate from the withdrawn heating medium to the first-mentioned body of water.

3. The method of supplying a mixed fluid heataiosmo ing medium consisting of products of combustion and steam, consisting in burning fuel within a closed combustion space, supporting anexposed body of water within the upper portion of the space so that it will expand when heated and overflow through the rising products of combustion, withdrawing the mixed heating medium from the closed space, and returning the condensate from the withdrawn heating medium to the body of water.

4. The method ofsupplying a heating medium consisting in causing products of combustion to flow upwardly through a space surrounded by a body of water retained with capacity to overflow into the space so that the overflow will be vaporized by and mixed with the products of combustion to form a heating medium, withdrawing this heating medium from the space and returning the condensate from the heating medium to said body of water.

5. In a heating system, a generator for a mixed fluid heating medium consisting of products l.of

combustion and steam, comprising a closed housing containing a combustion chamber, a burner for introducing fuel and air to the combustion chamber, an annular container within the housing partially surrounding the combustion chamber and supporting a body of water in surface contact with the combustion gases, a container for supporting a second body of water within the housing in the path of the rising products of combustion, the water overilowing through the combustion gases from one container to another, means for supplying water to the container positioned at the greatest elevation, and an outlet for the heating medium leading from the upper portion of the housing.

6. In a heating system, a generator for a mixed fluid heating medium consisting of products of combustion and steam, comprising a closed housing consisting of a lower chamber and an upper mixing chamber, a separating wall between the chambers, a refractory combustion chamber mounted in this wall, an air inlet to the lower chamber, a burner in the lower chamber for directing fuel and air into the combustion chamber, the combustion chamber being in open communication at its upper end with the mixing chamber, an open container for a body of water within the mixing chamber, means for supplying water to the container and an outlet for the heating medium leading from the upper portion of the housing.

7. In a heating system, a generator for a mixed fluid heating medium comprising a closed housing containing a combustion chamber in its lower portion and a mixing chamber thereabove and in open communication with the combustion chamber, an annular water container surrounding the combustion and mixing chambers, and`00 open at its upper end to overflow into the mixing chamber, an outlet for heating lmedium leading from the upper portion of the housing, an inlet for returning water to the container, a burner for introducing combustion materials to the combustion chamber, and an open heating pan supported within the mixing chamber, and a flashpan below the heating pan, the water overllowing from the container through the rising products of combustion onto the heating pan and thence onto the flash-pan.

8. In a heating system, a generator for a mixed fluid heating medium comprising a closed housing containing a combustion chamber in its lower portion and a mixing chamber thereabove and in open communication with the combustion chamber, an annular water container surrounding' the combustion and mixing chambers and open at its upper end to overflow into the mixing chamber, an open heating pan in the upper central portion of the mixing chamber into which the water overilows from the container, said pan being formed with a circumferential series of restricted outlet Openings in its side walls adjacent the upper edge thereof, a hash-pan below the l0 heating pan and in the path oi the rising products of combustion, the overilow thrn/igh the outlet openings of the heating pan falling through the mixing chamber onto the flash-pan, an outlet for the heating medium leading from the upper portion of the housing, an inlet for returning water to the container, and a burner for introducing combustion materials into the combustion chamber.

CLAYTON A. DUNHAM. AUBRA R. DUNHAM. 

